1. Field of the Invention
This invention relates to novel reactive coatings which can be cured at room temperature or force dried at temperatures ranging up to about 350.degree. F. The coatings may be utilized as primers, topcoats or as clearcoats and/or basecoats in clearcoat/basecoat compositions. The combination of acid-functional compounds, anhydride-functional compounds, and epoxy-functional compounds, especially cycloaliphatic epoxy compounds, provides fast reacting, durable coatings which minimize the toxicity problems which may be associated with other low temperature curing systems.
2. Description of the Prior Art
Many prior art approaches to high performance low temperature curing coatings have involved two component coatings comprising reactive polyisocyanates and active hydrogen-containing compounds such as hydroxyl-containing polymers or amine-containing polymers to produce polyurethane or polyurea coatings. Although these materials have excellent performance and cure at low temperatures, the isocyanates may, under some conditions, be relatively hazardous to handle.
Coating compositions comprising reactive combinations of epoxy-containing compounds and compounds having acid or amine functionality are known in the art. Similarly, coating compositions comprising cyclic anhydrides and epoxy-functional compounds are also known in the art. The prior art has not, however, taught the combination of anhydride-functional compounds, acid-functional compounds, and epoxy-functional compounds to provide low temperature curing coatings having excellent durability and performance.